During the treatment of waste water or polluted water, it is often necessary to aerate the water. As used herein, the terms "waste water" and "polluted water" are used interchangeably. During the process of aeration, a sufficient amount of oxygen is furnished to the water so as to allow the elimination of contaminants by multiplying aerobic bacteria in the water being treated. This plays an important part in the degradation process of the organic wastes contained in the water.
The uncontrolled growth of the world's population has simultaneously produced a problem of great magnitude. This problem is an insufficient supply of water needed to satisfy the demand for water. The irrational use of water, and its pollution, has appreciably aggravated the supply of water. The pollution of water through the lack of control of contaminated industrial waste has made obsolete the natural systems traditionally used to assist in the decontamination of water, such as river channels. Such river channels are no longer sufficient to degrade the organic material from sewage discharges.
In an attempt to solve this problem, the installation of industrial plants to treat the waste water has been promoted. However, the percentages of organic and fecal matter have increased to the point that these plants, which were initially efficient, have now been overcome by the problem and have been left idle because of poor results. As an example, over half of the waste water treatment plants which were installed in Mexico have fallen into disuse. The rest of such waste water treatment plants have been operating with great deficiencies and inefficiencies.
There are various techniques that can be used for the introduction of air into the water for the purpose of aerating the waste water. For example, mechanical waterfalls have been used to break up the water in a fashion similar to the flow in rivers and streams. Unfortunately, this action is not sufficient because the channels in rivers and streams contain abundant spaces and unevenness. These are conditions that cannot be obtained in a treatment plant of this type. In the treatment plants, such spaces are reduced and the unevenness or drops are limited. In this manner, the aeration of the water in these mechanical waterfalls has been very low in comparison with that obtained in the channels of rivers or streams.
Aeration tanks have been used for the purpose of treating polluted water. In aeration tanks, water passes through a tank with orifices. The intent of this process is that the liquid absorbs the air entering through these holes. Since this action is considered natural, not forced, the air does not penetrate the flow of water because the water offers resistance. Consequently, the results of this device discourage its use.
Another technique used for the treatment of polluted water is the use of agitators and mechanical revolving devices. These can be subdivided into two types: (1) the surface agitator and (2) the submerged revolving device. The surface water agitator is installed in a tank with previously calculated dimensions. The action of the agitator breaks up the water so as to force it to take in air from the surface. Although this action is efficient, it is limited to aerating the water located within a few centimeters of the surface. Unfortunately, it is unable to agitate the deeper water. Subsequently, there is no aeration and the transference of oxygen to all of the water in the tank is not accomplished. Consequently, although this device permits a good assimilation of air to the surface water, it has the disadvantage of providing almost no aeration at the bottom of the tank. The surface water agitator also has the disadvantage of creating a "short circuit." When the surface water is sufficiently aerated, it promotes the reproduction of aerobic bacteria. However, on the bottom of the tank, the desired aeration is not found. As such, the reproduction of anaerobic bacteria occurs. This causes the "short circuit" since the oxidizing enzymes from the aerobic bacteria kill the anaerobic bacteria and vice versa.
The submerged revolving device is an apparatus which moves water from the deeper parts. Unfortunately, large amounts of electricity are required so as to break up the water. Without this large amount of power, the agitation is not performed in the required efficient manner so as to obtain the necessary aeration. This device requires a high consumption of electrical current so as to achieve a vigorous agitation of the water to be treated. The high power consumption of such a device presents a great disadvantage.
Air blowers have been used for the aeration of water. Various types of air blowers have been employed in the past in an attempt to achieve the proper aeration of water. Air blowers are devices that can supply large amounts of air at relatively low pressure. This presents a great disadvantage since water, an element which presents more resistance than air, does not allow the air to penetrate easily. Consequently, the results of water aeration through the use of air blowers has been deficient.
Compressors and turbo compressors have been used in an effort to find an apparatus that could efficiently furnish air to water for the purposes of oxygenating polluted water. These devices introduce air at higher pressures. This equipment requires a high consumption of electrical energy so as to achieve its purposes. From a cost-benefit analysis, the use of compressors and turbo compressors cannot be justified for the treatment of waste water or for the treatment of polluted water.
It is evident that all of the devices described hereinabove have attempted to solve the problem by introducing air to water. This has resulted in various complications. Because of the density difference between water and air, the water will present resistance to the introduction of air. In order to reach this objective, an expensive piece of equipment is required which can consume a large amount of energy. Additionally, whenever air is introduced in the water using high pressure, the air enters at high velocity and exits to the surface at practically the same velocity. Under these conditions, little oxygen is yielded to the water. It is doubtful that the results justify the investment.
It is an object of the present invention to provide a device and method for the treatment of contaminated water which is both efficient and economical.
It is another object of the present invention to provide a method and apparatus for the treatment of water which maximizes the surface area available for contact between the oxygen and the air.
It is a further object of the present invention to provide a method and apparatus for the treatment of polluted water which relies on natural reactions between water and air.
It is still a further object of the present invention to provide an apparatus and method for the treatment of waste water which is more cost-effective than conventional equipment.
It is still a further object of the present invention to provide a waste water treatment device which is easily adaptable to the various conditions which apply at the site.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.